CN107731805A - Optical coupler and packaging method thereof - Google Patents

Abstract

The present invention provides an optical coupler and a packaging method thereof. The optical coupler reflects a first light directly emitted from the light-emitting chip, a second light directly emitted from the light-emitting chip, and a third light directly emitted from the light-emitting chip and then reflected by the first reflection surface or the second reflection surface to the light-receiving chip through a first reflection surface and a second reflection surface of an optical reflection surface. The present invention solves the problem of poor light-receiving efficiency of an optical coupler packaged by a planar secondary sealing process, and improves the current conversion ratio of a planar secondary sealing process package.

Description

Optical coupler and packaging method thereof

technical field

The invention relates to the field of optical couplers, in particular to an optical coupler and a packaging method thereof.

Background technique

In general, the traditional manufacturing process of optocouplers in the industry is divided into two types: flat primary sealing process and upper and lower fitting secondary sealing process.

Fig. 1 is a cross-sectional view of an optocoupler packaged according to a planar one-time sealing process of the related art. The planar one-time sealing process uses a pair of infrared LEDs and a light-receiving chip to be combined and placed on a planar support, with a large volume of transparent The silica gel completely covers the infrared LED, light-receiving chip, and part of the bracket. The silica gel will naturally present an egg shape (Dome) during molding, and then it is sealed with an outer plastic sealant (usually white epoxy resin containing TiO2) with infrared light reflection properties. encapsulation.

The advantages of the optocoupler packaged by the planar one-time sealing process are: the planar support does not cover each other between the light-emitting and receiving supports, so the common mode rejection phenomenon (CMR, Common Mode Reject) is better; the optocoupler packaged by this process Common problems are: poor bonding between silica gel and epoxy resin, in the important electrical high-voltage insulation test (Hi-Pot Test) of optocouplers, a high voltage is applied to measure the leakage current at the light-emitting and light-receiving ends, generally 3.75kV or more than 5kV), there are many failures. At present, the industry usually uses plasma cleaning on the surface of silica gel to strengthen its bonding.

Figure 2 is a cross-sectional view of an optocoupler packaged according to the upper and lower fitting secondary sealing process of the related technology. The upper and lower fitting secondary sealing process uses a pair of infrared LEDs and light-receiving chips to be placed at both ends of the upper and lower brackets. , use small-volume silica gel to cover only the infrared LED chip and part of the bracket, first encapsulate the light-emitting and light-receiving ends with a light-transmitting inner plastic encapsulant, and then use a non-reflective plastic encapsulant (usually carbon-containing) Black black epoxy resin) for encapsulation.

The optocoupler packaged by the upper and lower fitting secondary sealing process can effectively solve the problem of high-voltage test failure caused by the poor combination of silicone and epoxy resin because the silicone is controlled at the light-emitting end, and because the light-emitting chip and the light-receiving chip are facing each other , so it is easy to meet the current conversion ratio (CTR) requirements. This upper and lower embedding secondary sealing process is a more popular production method in the current Asian optocoupler packaging factories; its main disadvantage is that the common mode rejection phenomenon is relatively serious, and it cannot meet the electrical requirements for high-speed optocoupler (>1Mbit) products. need.

Figure 3 is a cross-sectional view of an optocoupler packaged according to the planar secondary sealing process of the related art. The planar secondary sealing process uses a planar bracket to place the light-emitting chip and the light-receiving chip, and coats the light-emitting chip with small-volume silica gel. The light-transmitting inner plastic encapsulant covers the light-emitting and light-receiving ends. The inner plastic encapsulant naturally assumes the shape of an egg during the molding process, and then the inner plastic encapsulant is wrapped with a reflective outer plastic encapsulant to complete the package.

The planar support of the optocoupler packaged by the planar secondary sealing process does not cover each other between the emitting and receiving supports, so the common mode rejection phenomenon is better; at the same time, because the silicone is controlled at the light emitting end, it can effectively solve the problem of silicone and the ring. Poor bonding of epoxy resin causes high pressure test failure. It can be seen that the flat secondary sealing process has the advantages of the flat primary sealing process and the upper and lower fitting secondary sealing process.

However, during the research process, it was found that the optocoupler packaged by the planar secondary sealing process did not adopt the upper and lower alignment structure of the light-emitting chip and the light-receiving chip of the secondary sealing process. The light-receiving efficiency of the packaged optocoupler is poor, which in turn affects its current conversion ratio.

Aiming at the problem of poor light-receiving efficiency of the optical coupler packaged by the planar secondary sealing process, no effective solution has been proposed so far.

Contents of the invention

The invention provides an optical coupler and a packaging method thereof to at least solve the problem of poor light collection efficiency of the optical coupler packaged by a plane secondary sealing process.

According to one aspect of the present invention, an optical coupler is provided, comprising:

A light-emitting chip for emitting light;

a first bracket, for setting the light-emitting chip;

A light-receiving chip for receiving light;

The second bracket is used to set the light-receiving chip;

Light-transmitting sealing glue, covering the light-emitting chip;

A transparent inner package, covering the light-transmitting sealant and the light-receiving chip;

an outer package covering the transparent inner package, the outer package has an optical reflective surface in contact with the transparent inner package;

Wherein, the first support and the second support are disposed opposite to each other on the same plane, and the first support and the second support respectively extend from the transparent inner package to the outer package in opposite directions;

The light-emitting chip and the light-receiving chip are arranged facing the optical reflection surface;

The optical reflective surface includes: a first reflective surface and a second reflective surface, the first reflective surface is arranged close to the light-emitting chip, and the first reflective surface is used to direct the first light emitted from the light-emitting chip reflected to the light-receiving chip; the second reflective surface is set close to the light-receiving chip, and the second reflective surface is used to reflect the second light directly emitted from the light-emitting chip and the second light directly emitted from the light-emitting chip The chip then reflects the third light reflected by the first reflective surface or the second reflective surface to the light-receiving chip.

Optionally, the first bracket includes a first installation bracket and a first wire bracket; wherein,

The light-emitting chip is arranged on the first installation bracket, and one wire of the light-emitting chip is electrically connected to the first installation bracket, and the other wire of the light-emitting chip is connected through the light-transmitting sealant leading out to the transparent inner package and electrically connected to the first lead bracket;

The first installation bracket and the first wire bracket respectively extend from the transparent inner packaging body to the outer packaging body.

Optionally, the second bracket includes a second installation bracket and a second wire bracket; wherein,

The light-receiving chip is arranged on the second installation bracket, and one wire of the light-receiving chip is electrically connected to the second installation bracket, and the other wire of the light-receiving chip is connected to the first installation bracket. Two wire brackets are electrically connected;

The second mounting bracket and the second wire bracket respectively extend from the transparent inner packaging body to the outer packaging body.

Optionally, the transparent inner package further includes a flat eaves portion, and the flat eaves portion is disposed under the optical reflection surface.

Optionally, the light-transmitting sealant is hemispherical, and the light-transmitting sealant includes transparent silica gel.

Optionally, the distance between the first bracket and the second bracket is 0.4 mm to 3 mm.

Optionally, the optical reflective surface is obtained by using the light-emitting chip to perform light collection benefit simulation.

According to another aspect of the present invention, an optical coupler packaging method is also provided, including:

Installing the light-emitting chip and the light-receiving chip on the first support and the second support that are horizontally opposite to each other;

encapsulating the light-emitting chip with light-transmitting sealing glue;

Design an optical reflective surface, wherein the optical reflective surface includes: a first reflective surface and a second reflective surface, the first reflective surface is arranged close to the light-emitting chip, and the first reflective surface is used to directly emit light from the The first light from the light-emitting chip is reflected to the light-receiving chip; the second reflective surface is arranged close to the light-receiving chip, and the second reflective surface is used to directly emit the second light from the light-emitting chip and Reflecting to the light-receiving chip from the third light directly emitted from the light-emitting chip and then reflected by the first reflective surface or the second reflective surface;

Covering the light-transmitting sealant and the light-receiving chip with a transparent inner package, and making the top surface of the transparent inner sealant present the same shape as the optical reflection surface;

The transparent inner packaging body is covered with an outer packaging body having a reflective property.

Optionally, the optical reflective surface is obtained by using the light-emitting chip to perform light collection benefit simulation.

According to the present invention, the optical coupler and its packaging method adopted, through the first reflective surface and the second reflective surface of the optical reflective surface, the first light directly emitted from the light-emitting chip, the light emitted directly from the light-emitting chip The second light and the third light that is directly emitted from the light-emitting chip and then reflected by the first reflective surface or the second reflective surface are reflected to the light-receiving chip, which solves the problem of the planar secondary sealing process The problem of poor light-receiving efficiency of the packaged optocoupler improves the current conversion ratio of the planar secondary sealing process.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 is a cross-sectional view of an optical coupler packaged according to a planar one-time sealing process of the related art;

Fig. 2 is a cross-sectional view of an optocoupler packaged according to the upper and lower fitting secondary sealing process of the related art;

3 is a cross-sectional view of an optical coupler packaged according to a planar secondary sealing process of the related art;

4 is a cross-sectional view of an optical coupler according to an embodiment of the present invention;

5 is a perspective view of an optical coupler according to an embodiment of the present invention;

6 is a cross-sectional view of an optical coupler according to an embodiment of the present invention;

7 is one of the cross-sectional views of an optical coupler according to an embodiment of the present invention;

Fig. 8 is a second cross-sectional view of an optical coupler according to an embodiment of the present invention;

9 is a flow chart of an optical coupler packaging method according to an embodiment of the present invention;

In Figures 1 to 3, the symbols represent the following meanings: ① transparent silica gel; ② light-emitting chip; ③ light-receiving chip; ④ wire; ; ⑧ has a light-transmitting inner plastic sealant.

detailed description

Hereinafter, the present invention will be described in detail with reference to the drawings and examples. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence.

An optical coupler is provided in this embodiment. FIG. 4 is a cross-sectional view of an optical coupler according to an embodiment of the present invention. As shown in FIG. 4, the optical coupler includes:

A light-emitting chip 1 for emitting light;

The first bracket 2 is used to set the light-emitting chip 1;

A light-receiving chip 3 for receiving light;

The second bracket 4 is used to set the light-receiving chip 3;

Light-transmitting sealing glue 5, covering the light-emitting chip 1;

A transparent inner package body 6, covering the light-transmitting sealant 5 and the light-receiving chip 3;

The outer package 7 covers the transparent inner package 6, and the outer package 7 has an optical reflective surface 8 in contact with the transparent inner package 6;

Wherein, the first bracket 2 and the second bracket 4 are arranged opposite to each other on the same plane, and the first bracket 2 and the second bracket 4 respectively extend from the transparent inner package body 6 to the outer package body 7 in opposite directions;

The light-emitting chip 1 and the light-receiving chip 3 are arranged facing the optical reflection surface 8;

The optical reflective surface 8 includes: a first reflective surface 81 and a second reflective surface 82, the first reflective surface 81 is arranged close to the light-emitting chip 1, and the first reflective surface 81 is used to reflect the first light 11 directly emitted from the light-emitting chip 1 to The light-receiving chip 3; the second reflective surface 82 is arranged close to the light-receiving chip 3, and the second reflective surface 82 is used to direct the second light 12 emitted from the light-emitting chip 1 and the second light 12 directly emitted from the light-emitting chip 1 to pass through the first reflective surface 81 or the third light 13 reflected by the second reflective surface 82 is reflected to the light-receiving chip 3 .

The optical reflection surface 8 of the embodiment of the present invention is different from the egg-shaped light reflection surface. Although the egg-shaped light reflective surface of the traditional planar secondary sealing process can be optimized by optical simulation or optical calculation, it is impossible to optimize the light-gathering efficiency of the light-emitting chip end and the light-receiving chip end respectively. In addition, the egg-shaped reflective surface has a better concentrating effect on the light along the straight line direction where the light-receiving chip and the light-emitting chip are located. , it is difficult to converge it to the receiving chip for reception.

In the optical coupler with the above structure provided in this embodiment, its optical reflective surface 8 is closer to the optimized first reflective surface of the light-emitting chip 1 than the egg-shaped light reflective surface of the traditional planar secondary sealing process. 81 optimally converges the first light 11 directly emitted from the light-emitting chip 1 to the light-receiving chip 3; the optimized second reflective surface 82 close to the light-receiving chip 3 directs the second light 12 directly emitted from the light-emitting chip 1 and The third light 13 that is directly emitted from the light-emitting chip 1 and then reflected by the first reflective surface 81 or the second reflective surface 82 is optimally converged to the light-receiving chip 3. Light can also achieve a better light-gathering effect through the first reflective surface 81 and the second reflective surface 82; it can be seen that the optical coupler provided in this embodiment can increase the light-collecting benefit, thereby solving the problem of the planar secondary sealing process. The problem of poor light collection efficiency of the existing optocoupler improves the current conversion ratio of the planar secondary sealing process.

In the above embodiments, the light-emitting chip 1 of the optical coupler is preferably an infrared light-emitting diode, but it is not limited thereto in the present invention. For example, the light emitting chip 1 may also be a visible light emitting diode, a laser light emitting diode, a plasma light emitting diode, or other light emitting components.

In the above embodiments, the light-receiving chip 3 is preferably a phototransistor capable of receiving infrared light, but it is not limited thereto in the present invention. For example, the light-receiving chip 3 may also be a photoresistor, a photodiode, a silicon-controlled rectifier (SCR), or other photosensitive components capable of converting light signals into electrical signals.

In the above embodiments, the material of the transparent inner package body 6 is preferably epoxy resin. Of course, the transparent inner packaging body 6 can also be made of other transparent materials. The material of the outer package 7 includes epoxy resin and titanium dioxide, so as to reflect light by utilizing the white color of the optical reflection surface 8 . Certainly, the material of the outer package body 7 is not limited thereto, and other materials capable of reflecting light can also be selected.

FIG. 5 is a perspective view of an optical coupler according to an embodiment of the present invention. In FIG. 5 , for the convenience of describing the transparent inner package 6 and its internal structure, the outer package 7 of the optical coupler is not shown. As shown in Figure 5, optionally, the above-mentioned first support 2 is preferably made of conductive metal material, and the first support 2 includes a first installation support 21 and a first wire support 22; wherein, the light-emitting chip 1 is arranged on the first Placed on the bracket 21, and one wire of the light-emitting chip 1 is welded on the first mounting bracket 21 to realize electrical connection, and the other wire of the light-emitting chip 1 is led out from the light-transmitting sealant 5 to the transparent inner package body 6, and welded The electrical connection is realized on the first lead frame 22 ; the first installation frame 21 and the first lead frame 22 respectively extend from the transparent inner package body 6 out of the outer package body 7 .

Continuing to refer to FIG. 5 , optionally, the above-mentioned second bracket 4 is also preferably made of a conductive metal material, and the second bracket 4 includes a second installation bracket 41 and a second wire bracket 42; wherein,

The light-receiving chip 3 is arranged on the second installation bracket 41, and one wire of the light-receiving chip 3 is welded on the second installation bracket 41 to realize electrical connection, and the other wire of the light-receiving chip 3 is welded on the second wire bracket 42 to realize electrical connection; the second mounting bracket 41 and the second wire bracket 42 respectively extend from the transparent inner packaging body 6 out of the outer packaging body 7 .

FIG. 6 is a cross-sectional view of an optical coupler according to an embodiment of the present invention. FIG. 6 shows a first reflective surface 81 and a second reflective surface 82 .

Optionally, the transparent inner package 6 further includes a flat eaves portion 61 , and the flat eaves portion 61 is disposed under the optical reflection surface 8 . Fig. 7 is one of the sectional views of an optical coupler according to an embodiment of the present invention. As shown in Fig. 7, the surface of the upper convex body of the transparent inner package 6 is consistent with the shape of the light reflecting surface 8, and the transparent inner package The lower portion of the body 6 is a flat eaves portion 61 . In Fig. 7, the flat eaves 61 are located below the first bracket 2 and the second bracket 4, and the bottom surface of the convex body on the top of the transparent inner package 6 is located directly above the flat eaves 61, and the bottom surface of the convex body is slightly smaller than or equal to The top surface of the flat eaves portion 61 .

Fig. 8 is the second cross-sectional view of an optical coupler according to an embodiment of the present invention. As shown in Fig. 8, the first support 2 and the second support 4 extend from the flat eaves 61, and the upper part of the transparent inner package 6 The bottom surface of the convex body is located directly above the flat eaves portion 61 , and the bottom surface of the convex body is smaller than the top surface of the flat eaves portion 61 .

Optionally, in this embodiment, the light-transmitting sealant 5 is preferably hemispherical, and the light-transmitting sealant 5 is preferably transparent silica gel. Of course, the present invention is not limited thereto, and the light-transmitting sealant 5 can also be replaced by other light-transmitting substances with good heat dissipation.

Optionally, the distance between the first bracket 2 and the second bracket 4 is 0.4 mm to 3 mm.

Optionally, for different light-emitting chips, there are different light distributions, that is, different emission angles have different light intensity characteristics. However, for the same kind of light-emitting chips, the distribution of light patterns is the same or almost the same. Therefore, for the same light-emitting chip, the shape of the optical reflection surface with higher or highest light-receiving efficiency under natural lighting conditions can be simulated by means of light-receiving effect simulation. The simulated optical reflective surface with higher or highest light collection efficiency is called the optical reflective surface 8 in this embodiment.

In the embodiment of the present invention, Solidworks is preferably used to establish an optical simulation model, and Lighttools optical simulation software is used for analysis. In the established optical simulation model, the relative positions of the fixed light-emitting chip and the light-receiving chip, the light-emitting pattern of the light-emitting chip (including the light-emitting angle and the light intensity at each light-emitting angle), and the reflection conditions of the reflective surface are used. At the same time, an optical simulation model of the egg-shaped light reflecting surface is also established. Except that the optical reflecting surface is an egg-shaped light reflecting surface, other conditions of the model are consistent with the optical simulation model of the embodiment of the present invention for comparison.

A simulation result shows that the light-receiving chip of the optical simulation model of the egg-shaped light reflecting surface receives 4.6 units of luminous flux, and there are 14,753 light beams in total, while the optical reflecting surface with two reflecting surfaces obtained through simulation is 8 The light-receiving chip of the optical simulation model can receive up to 6.3 units of luminous flux, and there are 17409 light-receiving beams.

The optical simulation model with the optical reflection surface 8 has 2656 more light beams than the optical simulation model with the egg-shaped light reflection surface. Since the intensity of each light beam is different, it may not be meaningful to simply compare the number of light beams. Therefore, comparing the optical simulation model of the traditional egg-shaped light reflection surface with the optical simulation model with the optical reflection surface 8 by representing the light collection efficiency with the luminous flux, it is found that the optical simulation model with the optical reflection surface 8 can increase the collection efficiency by about 35%. amount of light. It can be seen that the light collection efficiency can be greatly improved by using the optical reflection surface 8 of the embodiment of the present invention.

In addition, due to the design of the optical reflection surface 8, the luminous flux emitted by the light-emitting chip 1 and reflected on the light-receiving chip 3 can be changed. Different optical reflection surfaces 8 can also control the current conversion ratio of the optical coupler.

In this embodiment, an optical coupler packaging method is also provided. Fig. 9 is a flowchart of an optical coupler packaging method according to an embodiment of the present invention. As shown in Fig. 9, the process includes the following steps:

Step S901, installing the light-emitting chip and the light-receiving chip on the first support and the second support that are horizontally opposite to each other;

Step S902, encapsulating the light-emitting chip with a light-transmitting sealant;

Step S903, designing an optical reflective surface, wherein the optical reflective surface includes: a first reflective surface and a second reflective surface, the first reflective surface is set close to the light-emitting chip, and the first reflective surface is used to direct the first light emitted from the light-emitting chip Reflected to the light-receiving chip; the second reflective surface is set close to the light-receiving chip, and the second reflective surface is used to direct the second light emitted from the light-emitting chip and the second light directly emitted from the light-emitting chip through the first reflective surface or the second reflective surface The reflected third light is reflected to the light-receiving chip;

Step S904, using a transparent inner package to cover the light-transmitting sealant and the light-receiving chip, and making the top surface of the transparent inner sealant present the same shape as the optical reflection surface;

Step S905, covering the transparent inner package with the reflective outer package.

Optionally, the above-mentioned optical reflection surface 8 is a reflection surface whose light collection efficiency is higher than that of the egg-shaped light reflection surface obtained by using light-emitting chips to simulate light collection efficiency.

The optical coupler provided by the embodiment of the present invention adopts two kinds of reflective surfaces with no curvature at the end of the light-receiving chip and the end of the light-emitting chip, so it is also called a double-curvature optical coupler. Compared with the related technology, the double curvature optical coupler adopts the optical reflection surface method after optical simulation and calculation. The reflective surface of the light-emitting chip cooperates with the light-emitting angle and light pattern of the light-emitting chip to perform light-condensing action, and the light emitted by the light-emitting chip The light is focused on the sensing area of the light-receiving chip; the reflective surface at the end of the light-receiving chip effectively captures the lost light and refocuses the sensing area of the light-receiving chip. The advantage of the double-curvature optical coupler is that the planar support does not cover each other between the light-emitting and receiving supports, so the common-mode rejection phenomenon is better; and the silicone is only on the light-emitting chip end, and there is no high-voltage failure problem; after optical simulation and calculation, the optical reflection The design of the surface can effectively concentrate the light beam and reflect it on the light-receiving chip with a fixed area, and can effectively control the range of the current conversion ratio of the product.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. An optical coupler, comprising:

a light emitting chip for emitting light;

the first bracket is used for arranging the light-emitting chip;

the light receiving chip is used for receiving light;

the second bracket is used for arranging the light receiving chip;

the light-transmitting sealing glue coats the light-emitting chip;

the transparent inner packaging body wraps the light-transmitting sealant and the light receiving chip;

an outer package body wrapping the transparent inner package body, the outer package body having an optical reflection surface in contact with the transparent inner package body;

the first support and the second support are oppositely arranged on the same plane, and extend out of the outer packaging body from the transparent inner packaging body in opposite directions respectively;

the light emitting chip and the light receiving chip are arranged facing the optical reflection surface;

the optical reflection surface includes: the first reflecting surface is arranged close to the light emitting chip and used for reflecting first light rays directly emitted from the light emitting chip to the light receiving chip; the second reflecting surface is arranged close to the light receiving chip and used for reflecting second light rays directly emitted from the light emitting chip and third light rays directly emitted from the light emitting chip and reflected by the first reflecting surface or the second reflecting surface to the light receiving chip.

2. The optical coupler of claim 1, wherein the first bracket includes a first mounting bracket and a first wire bracket; wherein,

the light-emitting chip is arranged on the first arranging support, one conducting wire of the light-emitting chip is electrically connected with the first arranging support, and the other conducting wire of the light-emitting chip is led out of the light-transmitting sealing adhesive to the transparent inner packaging body and is electrically connected with the first conducting wire support;

the first mounting bracket and the first wire bracket extend out of the outer packaging body from the transparent inner packaging body respectively.

3. The optical coupler of claim 1, wherein the second bracket includes a second mounting bracket and a second wire bracket; wherein,

the light receiving chip is arranged on the second mounting bracket, one wire of the light receiving chip is electrically connected with the second mounting bracket, and the other wire of the light receiving chip is electrically connected with the second wire bracket;

the second mounting bracket and the second wire bracket extend out of the outer packaging body from the transparent inner packaging body respectively.

4. The optical coupler of claim 1, wherein the transparent inner encapsulant further comprises a flat brim disposed below the optically reflective surface.

5. The optical coupler of claim 1, wherein the light transmissive encapsulant is hemispherical, and the light transmissive encapsulant comprises transparent silicone.

6. The optical coupler of claim 1, wherein the distance between the first leg and the second leg is 0.4mm to 3 mm.

7. The optical coupler according to any one of claims 1 to 6, wherein the optical reflection surface is obtained by performing a light receiving efficiency simulation using the light emitting chip.

8. A method of packaging an optical coupler, comprising:

respectively installing a light emitting chip and a light receiving chip on a first support and a second support which are horizontally arranged oppositely;

a light-transmitting sealing adhesive is used for coating the light-emitting chip;

designing an optically reflective surface, wherein the optically reflective surface comprises: the first reflecting surface is arranged close to the light emitting chip and used for reflecting first light rays directly emitted from the light emitting chip to the light receiving chip; the second reflecting surface is arranged close to the light receiving chip and used for reflecting second light rays directly emitted from the light emitting chip and third light rays directly emitted from the light emitting chip and reflected by the first reflecting surface or the second reflecting surface to the light receiving chip;

a transparent inner packaging body is adopted to coat the light-transmitting sealing glue and the light receiving chip, and the top surface of the transparent inner packaging glue is in the same shape as the optical reflection surface;

and the transparent inner packaging body is coated by the outer packaging body with the light reflecting property.

9. The method of claim 8, wherein the optical reflecting surface is obtained by performing a light receiving efficiency simulation using the light emitting chip.